This invention relates generally to turbines, and, more particularly, to seal ring assemblies for use with turbines.
At least some known seal assemblies used with turbines are biased open by a spring coupled thereto. More specifically, the spring induces a radially outward biasing force against a seal ring that increases a diameter of the seal ring. As pressure is increased within the turbine, the biasing force induced by the spring must be overcome to decrease the diameter of the seal ring to facilitate preventing steam flow through the seal assembly within the turbine. Accordingly, in such sealing assemblies, radial inward travel of the seal ring is generally delayed until pre-determined operating conditions for the turbine are attained.
At least some known seal assembly springs may be installed in the field during final assembly of the turbine. Specifically, the springs may be temporarily positioned against the seal ring using re-roundable dowels which do not provide positive retention and only retain the spring after the seal ring is installed in the packing assembly. As such the spring may fall out or be deformed during installation of the seal ring. Moreover, the seal ring can not be shipped with the spring pre-installed. Accordingly, such seal ring/spring assemblies may increase installation time, decrease quality, and increase overall costs associated with installation of the seal assembly.